In co-pending application Ser. No. 50,685, filed June 21, 1979, there is disclosed a percussor for directing energy created by successive bursts of gas to a user or patient. A gas sealing means separates gas inlet and gas outlet passageways, and gas is directed through the gas inlet passageway to a gas pressure chamber, the gas pressure building up until it overcomes the gas sealing means thereby creating a burst of gas which causes the reciprocating member to be moved. Other features of the apparatus disclosed in the aforesaid co-pending application are incorporated herein by reference.
A disadvantage of the aforesaid apparatus is in excessive gas requirements for its operation. When the gas sealing means is open, gas continues to pass from the gas inlet passageway, past the sealing means, and out through the gas outlet passageway resulting in a substantial loss of gas in excess of that required for moving the reciprocating member. Further, where the incoming gas pressure is substantially high, it can cause interruption of movement of the reciprocating member by forcing the gas sealing means to remain in the open position. It is to the elimination of such disadvantages that the present invention is directed.